If you like music, then I would recommend a trip to East London to visit the V&A Storehouse and V&A East, both of them have excellent exhibits (David Bowie for Storehouse and Music is Black for East). While I liked V&A Storehouse, V&A East has just opened and there is not much to see. One thing if you or your granddaughter are into fashion, we met some fashion students who arranged to check out some fabrics and were using that for their own design inspiration. You can find out how to check out items on the V&A Storehouse website.
If you have not been to East London on a Sunday, the markets are a blast. We were just there this past week and we found so many amazing unique creations, great vintage finds, and the food is amazing. We spent the morning there and really enjoyed soaking up the local vibes.
For Indian restaurants near Kensington, would recommend Dishoom. The food is amazing and it is housed in an old art deco building. In addition, they also have live music on Thursdays and Fridays.